The present invention relates to a lower frame for a pivoted window disposed on an outer wall such as a curtain wall.
A window frame structure of a square or another shape is defined on an opening of an outer wall such as a curtain wall by frames and a pivoted window is generally attached to a supporting device disposed in the central portion of the space between the lower and upper frames of the window frame structure. Although air-tight means is mounted on a pivoted window of this type, leakage or intrusion of rain water into the room cannot be avoided because the space defined by the frames of the window frame structure and rails and stiles of the pivoted window is sealed from outer air and a difference of the pressure is produced between this space and outer air by changes of the pressue in outer air. Accordingly, it has been difficult to obtain a pivoted window having good water tightness.